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Technologies / Lettermint B.V. / OpenAI

Companies using Lettermint B.V. and OpenAI

5 companies in our data have public evidence for both Lettermint B.V. and OpenAI, and 3 name both in their own subprocessor list. Each company below links to the source for every claim. Our coverage is partial, so this is not everyone.

5companies use both
28%of Lettermint B.V. users
under 1%of OpenAI users
3name both as subprocessors

Companies using one are 2.0 times as likely as the average company in our data to show evidence of the other.

The companies

Strongest evidence first: a company naming both in its own subprocessor list comes before one seen on its website or in job postings.

Subprocessor listPrivacy policyWebsiteJob postings

CompanyLettermint B.V.OpenAI
Lizaliza.appLiza is an AI coding and project management tool that combines projects, sprints, an AI assistant, Git workflow and team chat.AI and machine learningDeveloper tools
MeinGPTmeingpt.comMeinGPT provides an AI use-case platform with chat, models, assistants, meetings, integrations and tools for building and running AI use cases.AI and machine learningProductivity and collaboration
nurionnurion.comNurion provides a private, EU-sovereign AI workspace that combines meetings, documents, chat, mail, signing, task boards and an API for AI agents.AI and machine learningProductivity and collaboration
botts.aiAI and machine learning
Custos AIcustosai.euCustos reads business emails, looks up information in a company's existing systems, takes actions like drafting quotes or creating orders, and replies.

The two technologies

Lettermint B.V.

Email and communications

Lettermint is an email delivery service for transactional emails, broadcast newsletters and marketing campaigns, and inbound email processing. It is used to send and receive emails through SDKs, an API, SMTP, a CLI and integrations.

Summarized from lettermint.co on 8 Nov 2026.

28% of the 18 companies we see using Lettermint B.V. also show the other.

All 18 companies using Lettermint B.V.15 name it as a subprocessorMore in Email and communications

OpenAI

AI and LLM providers

OpenAI is a platform that provides an API for building with OpenAI models. It is used to access models, tools, and services for tasks such as text generation, image generation, audio, and agents.

Summarized from developers.openai.com on 8 Nov 2026.

under 1% of the 3,304 companies we see using OpenAI also show the other.

All 3,304 companies using OpenAI2,530 name it as a subprocessorMore in AI and LLM providers

Industries

Among the companies above, by our own classification of their homepage.

AI and machine learning4Productivity and collaboration3

Other pairs

Companies with their own evidence for both.

More with Lettermint B.V.

Cloudflare18companiesGoogle9companiesGoogle Workspace8companiesHetzner7companiesNext.js7companiesAnthropic6companies

More with OpenAI

Cloudflare3,282companiesGoogle Workspace2,476companiesAnthropic1,996companiesAmazon Web Services1,888companiesStripe1,647companiesGoogle1,549companies

Questions

How many companies use both Lettermint B.V. and OpenAI?

5 companies in StrataDB's data have public evidence for both, and 3 of them name both in their own subprocessor list, the strongest evidence we hold. Our coverage is partial, so the real number is higher.

Which companies use Lettermint B.V. and OpenAI?

Liza, MeinGPT, nurion, botts.ai and Custos AI. Each one links to the evidence behind it.

How does StrataDB know a company uses Lettermint B.V. and OpenAI?

From four kinds of public evidence: subprocessor lists, privacy policies, website code and job postings. Each is kept apart with its source and the date we saw it. A company missing here means we found no evidence, not that it does not use them.

Find every company using Lettermint B.V. and OpenAI

See the full list with the source for each company, and run the same lookup for any technology from the API, Claude or your browser.

  • Every company and vendor, with its public source
  • 100 API calls a month, plus MCP and the Chrome extension
  • Work email only. No card, no sales call